Nuprl Lemma : eu-seg-length-extend
∀[e:EuclideanPlane]. ∀[s:ProperSegment]. ∀[t:Segment].  (|s + t| = |s| + |t| ∈ {p:Point| O_X_p} )
Proof
Definitions occuring in Statement : 
eu-add-length: p + q, 
eu-length: |s|, 
eu-seg-extend: s + t, 
eu-proper-segment: ProperSegment, 
eu-segment: Segment, 
euclidean-plane: EuclideanPlane, 
eu-between-eq: a_b_c, 
eu-X: X, 
eu-O: O, 
eu-point: Point, 
uall: ∀[x:A]. B[x], 
set: {x:A| B[x]} , 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
eu-proper-segment: ProperSegment, 
eu-seg-proper: proper(s), 
eu-segment: Segment, 
eu-seg-extend: s + t, 
eu-seg2: s.2, 
eu-seg1: s.1, 
pi1: fst(t), 
pi2: snd(t), 
eu-mk-seg: ab, 
all: ∀x:A. B[x], 
top: Top, 
euclidean-plane: EuclideanPlane, 
prop: ℙ, 
implies: P ⇒ Q, 
uimplies: b supposing a, 
and: P ∧ Q, 
uiff: uiff(P;Q)
Lemmas referenced : 
eu_seg1_mk_seg_lemma, 
eu_seg2_mk_seg_lemma, 
eu-segment_wf, 
eu-proper-segment_wf, 
euclidean-plane_wf, 
eu-extend-property, 
not_wf, 
equal_wf, 
eu-point_wf, 
eu-extend_wf, 
eu-add-length-between, 
eu-congruent-iff-length, 
and_wf, 
eu-between-eq_wf, 
eu-O_wf, 
eu-X_wf, 
eu-add-length_wf, 
eu-length_wf, 
eu-mk-seg_wf, 
eu-congruent_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalHypSubstitution, 
setElimination, 
thin, 
rename, 
productElimination, 
sqequalRule, 
lemma_by_obid, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
hypothesis, 
isectElimination, 
hypothesisEquality, 
axiomEquality, 
because_Cache, 
dependent_set_memberEquality, 
lambdaFormation, 
independent_isectElimination, 
equalitySymmetry, 
independent_pairFormation, 
equalityTransitivity, 
setEquality, 
applyEquality, 
lambdaEquality, 
equalityEquality, 
independent_functionElimination
Latex:
\mforall{}[e:EuclideanPlane].  \mforall{}[s:ProperSegment].  \mforall{}[t:Segment].    (|s  +  t|  =  |s|  +  |t|)
Date html generated:
2016_05_18-AM-06_38_41
Last ObjectModification:
2015_12_28-AM-09_23_51
Theory : euclidean!geometry
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